Rotary drum brake assemblies are well known in the art of braking motor vehicles wheels. Such assemblies characteristically include a stationary backing or torque plate secured to the end of the axle and about which rotates a rotary drum to which the wheel is secured. The brake assembly features a pair of opposed brake shoe assemblies that are respectively pivotally mounted to the backing plate within the drum and carry frictional braking material facing theretowards. Upon application of the brakes, a mechanism, such as a rotary or a wedge cam disposed between the opposite end of the brake shoe assemblies, is caused to rotate or be axially displaced and spread the brake shoe assemblies apart for a distance sufficient to enable the braking material to frictionally engage the drum for the braking thereof.
At least one and often two or more resilient biasing members such as coiled springs (usually called "return springs") are employed to resiliently urge the brake shoe assemblies towards each other for a distance sufficient to disengage the frictional braking material from the drum upon release of the brake.
Examples of rotary drum brake assemblies and the various means employed to secure the biasing members so that they operate in the manner described above are disclosed in U.S. Pat. Nos. 2,064,103; 2,751,048; 2,788,866; 3,837,446; 4,064,978 and 4,216,850, the disclosures of all of which are incorporated herein by reference.
All of the above disclosed brake assemblies feature however the biasing members secured to both of the brake shoe assemblies or between each brake shoe assembly and a stationary bracket that is fixially secured to the locking plate most often at a location between the pivoted ends of the brake shoe assemblies rather than between the opposite end where the rotary cam or other brake shoe spreading mechanism is located.
Such stationary brackets characteristically require special drilling and tapping or other means of fixedly securing the bracket that are costly and time consuming to install and further require the expense and time of having to be loosened or removed in the event they block portions of the brake assembly hidden behind the bracket to which access is desired. Additionally, the collar or bracket of the invention enables the return springs to be located close to the actuating cam and thereby increasing the mechanical advantage in pivoting the brake shoe assemblies towards each other upon release of the brake.